Twin-to-Twin Transfusion Syndrome: Quintero Staging and Ultrasound Monitoring
Diagnostic Criteria and Quintero Staging
TTTS diagnosis is established based on measurement of the maximum vertical pocket of amniotic fluid: >8 cm in the recipient twin and <2 cm in the donor twin (ISUOG, 2024). Disease stage is determined according to the Quintero staging system.
Detailed ultrasound examination in suspected TTTS includes: measurement of amniotic fluid volume, fetal and maternal Doppler studies, anatomic survey, and fetal echocardiography using high-resolution equipment (Johns Hopkins Center for Fetal Therapy).
Limitations of the Quintero System
According to ISUOG (2025), Quintero staging does not reflect progressive disease deterioration (EVIDENCE LEVEL: 2+). In most cases, pathological Doppler findings preceded TTTS diagnosis, suggesting that more frequent surveillance does not necessarily lead to earlier stage diagnosis. Attempts to identify TTTS markers in the first trimester have, according to meta-analysis, been unsuccessful to date.
Management Strategy by Stage
| Quintero Stage | Recommended Management |
|---|---|
| Stage I | Individualized management: careful ultrasound surveillance (expectant management) or FLP if progression occurs |
| Stage II–IV (at 16–26 weeks) | Fetoscopic laser photocoagulation of anastomoses (FLP) — method of choice if technically feasible |
Maternal symptoms for which expectant management is not indicated: dyspnea, contractions, cervical length less than 20 mm. For progressive TTTS, selective reduction should be discussed with the patient as a treatment option (ISUOG, 2024).
Ultrasound Monitoring
With expectant management, sonographic evaluation is repeated once or twice per week depending on disease severity and includes monitoring of maternal symptoms and cervical length. With laser treatment, standard prenatal ultrasound is performed before surgery, at 1 day and 1 week after laser surgery, then at least once every two weeks, including screening for fetal brain injury (LUMC).
Frequently asked questions
What amniotic fluid criteria are used for TTTS diagnosis?
Maximum vertical pocket >8 cm in the recipient twin and <2 cm in the donor twin (ISUOG, 2024).
How frequently should ultrasound monitoring be performed with expectant management?
Sonographic evaluation is repeated 1-2 times per week depending on disease severity, with monitoring of maternal symptoms and cervical length.
At which Quintero stage is laser photocoagulation indicated?
Fetoscopic laser (FLP) is the method of choice at stages II–IV at 16–26 weeks if technically feasible. Stage I is managed individually.
Does Quintero staging reflect disease progression?
No. According to ISUOG (2025), Quintero staging does not reflect progressive disease deterioration (EVIDENCE LEVEL: 2+).
What studies are included in detailed ultrasound assessment in TTTS?
Measurement of amniotic fluid volume, fetal and maternal Doppler studies, anatomic survey, and fetal echocardiography.